Add toggle line comment command (issue #27)

Add an OPM Flow: Toggle Line Comment command that inserts or removes a
'--' marker at the absolute beginning of each selected line. If every
non-blank selected line is already commented the marker is removed;
otherwise '-- ' is prefixed at column 0. Blank lines are left untouched.

The toggle logic lives in a pure toggleLineComments() helper with unit
tests. The command is exposed via the editor context menu and bound to
Ctrl+/ (Cmd+/ on macOS), which VS Code resolves through the active
keyboard layout.

Author: magnesj

vscode-extension/README.md

@@ -172,6 +172,22 @@ VFPIDIMS
       30     20       20 /
 ```
 
+### Toggle Line Comment
+
+Select one or more lines and invoke **OPM Flow: Toggle Line Comment** (bound to
+`Ctrl+/`, or `Cmd+/` on macOS — VS Code maps this to the same physical key as the
+built-in comment toggle, so it follows your keyboard layout) — also available from
+the right-click menu — to
+add or remove a `--` comment marker at the very start of each selected line. If
+every non-blank line in the selection is already commented the marker is
+removed; otherwise `-- ` is inserted at column 0 of each line. Blank lines are
+left untouched.
+
+```
+-- WCONPROD
+--   'PROD' 'OPEN' /
+```
+
 ### File Navigation (INCLUDE / IMPORT / RESTART / GDFILE)
 
 Quoted file paths on `INCLUDE`, `IMPORT`, `RESTART`, and `GDFILE` statements

vscode-extension/package.json

@@ -130,6 +130,10 @@
       {
         "command": "opm-flow.addColumnHeaders",
         "title": "OPM Flow: Add Column Headers"
+      },
+      {
+        "command": "opm-flow.toggleLineComment",
+        "title": "OPM Flow: Toggle Line Comment"
       }
     ],
     "menus": {
@@ -143,9 +147,22 @@
           "command": "opm-flow.addColumnHeaders",
           "when": "resourceLangId == opm-flow",
           "group": "opm-flow"
+        },
+        {
+          "command": "opm-flow.toggleLineComment",
+          "when": "resourceLangId == opm-flow",
+          "group": "opm-flow"
         }
       ]
     },
+    "keybindings": [
+      {
+        "command": "opm-flow.toggleLineComment",
+        "key": "ctrl+/",
+        "mac": "cmd+/",
+        "when": "editorTextFocus && !editorReadonly && editorLangId == opm-flow"
+      }
+    ],
     "configuration": {
       "title": "OPM Flow",
       "properties": {

vscode-extension/src/extension.ts

@@ -17,6 +17,7 @@ import {
   formatRecordGroupWithHeading,
   buildHeadingAndAlignedRecords,
   tokenColumnCount,
+  toggleLineComments,
 } from './formatting';
 import { computeDiagnostics } from './analysis';
 import { findFileReferences } from './links';
@@ -1170,6 +1171,37 @@ export function activate(context: vscode.ExtensionContext): void {
     }
   });
 
+  // --- Command: toggle line comment (`--` at the absolute start of line) ---
+  const toggleCommentCommand = vscode.commands.registerCommand('opm-flow.toggleLineComment', async () => {
+    const editor = vscode.window.activeTextEditor;
+    if (!editor) return;
+    const doc = editor.document;
+
+    // Toggle every line touched by any selection (deduplicated). A decision
+    // (comment vs. uncomment) is made independently per contiguous selection
+    // so each behaves like the editor's native toggle.
+    await editor.edit(b => {
+      for (const sel of editor.selections) {
+        const firstLine = sel.start.line;
+        // An empty trailing line in the selection (cursor at column 0 of the
+        // line after the last selected character) should not be included.
+        const lastLine = sel.end.line > sel.start.line && sel.end.character === 0
+          ? sel.end.line - 1
+          : sel.end.line;
+        const originals: string[] = [];
+        for (let ln = firstLine; ln <= lastLine; ln++) {
+          originals.push(doc.lineAt(ln).text);
+        }
+        const toggled = toggleLineComments(originals);
+        if (!toggled) continue;
+        for (let k = 0; k < toggled.length; k++) {
+          if (toggled[k] === originals[k]) continue;
+          b.replace(doc.lineAt(firstLine + k).range, toggled[k]);
+        }
+      }
+    });
+  });
+
   const alignColumnsCommand = vscode.commands.registerCommand('opm-flow.alignRecordColumns', async () => {
     const editor = vscode.window.activeTextEditor;
     if (!editor) return;
@@ -1215,7 +1247,7 @@ export function activate(context: vscode.ExtensionContext): void {
     }),
   );
 
-  context.subscriptions.push(completionProvider, valueCompletionProvider, hoverProvider, generateReferenceCommand, addColumnHeadersCommand, alignColumnsCommand, fileLinkProvider, foldingProvider);
+  context.subscriptions.push(completionProvider, valueCompletionProvider, hoverProvider, generateReferenceCommand, addColumnHeadersCommand, alignColumnsCommand, toggleCommentCommand, fileLinkProvider, foldingProvider);
 }
 
 export function deactivate(): void {}

vscode-extension/src/formatting.test.ts

@@ -9,6 +9,7 @@ import {
   formatRecordGroupWithHeading,
   buildHeadingAndAlignedRecords,
   tokenColumnCount,
+  toggleLineComments,
   RecordLine,
 } from './formatting';
 
@@ -699,3 +700,58 @@ describe('columnForCompletion', () => {
     expect(columnForCompletion('', 0)).toBe(1);
   });
 });
+
+// ---------------------------------------------------------------------------
+// toggleLineComments
+// ---------------------------------------------------------------------------
+
+describe('toggleLineComments', () => {
+  test('comments uncommented lines at column 0', () => {
+    expect(toggleLineComments(['WCONPROD', '  PROD OPEN'])).toEqual([
+      '-- WCONPROD',
+      '--   PROD OPEN',
+    ]);
+  });
+
+  test('uncomments when every non-blank line is commented', () => {
+    expect(toggleLineComments(['-- WCONPROD', '--   PROD OPEN'])).toEqual([
+      'WCONPROD',
+      '  PROD OPEN',
+    ]);
+  });
+
+  test('removes only one space after the marker on uncomment', () => {
+    expect(toggleLineComments(['--  double space'])).toEqual([' double space']);
+    expect(toggleLineComments(['--no space'])).toEqual(['no space']);
+  });
+
+  test('comments all when the block is only partially commented', () => {
+    expect(toggleLineComments(['-- already', 'not yet'])).toEqual([
+      '-- -- already',
+      '-- not yet',
+    ]);
+  });
+
+  test('leaves blank lines untouched and ignores them in the decision', () => {
+    expect(toggleLineComments(['-- one', '', '-- two'])).toEqual([
+      'one',
+      '',
+      'two',
+    ]);
+  });
+
+  test('an indented marker is not treated as commented', () => {
+    expect(toggleLineComments(['  -- indented'])).toEqual(['--   -- indented']);
+  });
+
+  test('round-trips comment then uncomment', () => {
+    const original = ['RUNSPEC', '  DIMENS', '  10 10 3 /'];
+    const commented = toggleLineComments(original)!;
+    expect(toggleLineComments(commented)).toEqual(original);
+  });
+
+  test('returns null when there is nothing to toggle', () => {
+    expect(toggleLineComments([])).toBeNull();
+    expect(toggleLineComments(['', '   '])).toBeNull();
+  });
+});

vscode-extension/src/formatting.ts

@@ -178,6 +178,35 @@ export function isCommentLine(line: string): boolean {
   return /^\s*--/.test(line);
 }
 
+// ---------------------------------------------------------------------------
+// Line-comment toggle
+// ---------------------------------------------------------------------------
+
+/** A line is treated as commented for toggle purposes only when the comment
+ *  marker sits at the *absolute* start of the line (column 0). An indented
+ *  `--` is left alone so the toggle round-trips cleanly. */
+const LEADING_COMMENT_RE = /^--[ \t]?/;
+
+/**
+ * Toggle `--` line comments at the absolute beginning of each given line.
+ *
+ * Mirrors the editor's "toggle line comment" convention: if every non-blank
+ * line already starts with `--`, all of them are uncommented; otherwise every
+ * non-blank line is commented by prefixing `-- ` at column 0. Blank lines are
+ * left untouched. Returns the rewritten lines, or `null` when there is nothing
+ * to toggle (no non-blank lines).
+ */
+export function toggleLineComments(lines: string[]): string[] | null {
+  const nonBlank = lines.filter(l => l.trim() !== '');
+  if (nonBlank.length === 0) return null;
+  const allCommented = nonBlank.every(l => l.startsWith('--'));
+  return lines.map(l => {
+    if (l.trim() === '') return l;
+    if (allCommented) return l.replace(LEADING_COMMENT_RE, '');
+    return `-- ${l}`;
+  });
+}
+
 // ---------------------------------------------------------------------------
 // Column alignment helpers
 // ---------------------------------------------------------------------------